# P126--P128
vowels = set('aeiou')
word = 'hello'
print("vowels=",vowels)
print("word=",word)
print("------并集union------")
u = vowels.union(set(word)) #合并集合：union方法
print(u)

print("------差集difference------")
d =vowels.difference(set(word))
print(d)

print("------交集intersection------")
i = vowels.intersection(set(word))
print(i)